When I saw a headline indicating that 15 places in the US had “lost their total solar eclipse”, I was confused. A solar eclipse is not like weather, which changes frequently, nor is it subject to political lobbying and maneuvering. Instead, it’s a lot more like clockwork, and it’s something we can measure with extreme precision.

So what changed? Fascinatingly, our understanding of the radius of the sun. New calculations there mean the path of totality for the coming eclipse will be about 2000 feet narrower than previously thought. If you were right on the edge, move a half-mile (or more) inward.